1. Plato’s Forms

2. Plato 429-327 BC Student of Socrates (496-399)
Teacher of Aristotle ( )
Founded ‘Academy’
Wrote Dialogues
Theaetetus
Republic
Meno

3. Theaetetus A late treatment of knowledge
Dismisses two possibilities for knowledge
Perception
True belief
Proposes: True Belief with an Account
To know X is to truly believe X and to have an account of X
But what is an account? Justification for the belief?

4. Theaetetus
First possibility: an account is an analysis of how X is composed of simpler parts
So no simple thing can be known?
Reject this idea

5. Theaetetus
Second possibility: an account is a catalogue of the component parts
But you can list the parts of a chariot without having an understanding of the chariot itself.
Reject this idea

6. Theaetetus
Third possibility: an account is an identification of the distinguishing characteristic
To know X about the sun is for X to be a true belief and you can identify the sun as, say, the brightest object in the sky
But this means there is always something else to know before you can know any X
Reject this idea

7. Meno’s Paradox The Paradox of Inquiry
MENO: How will you look for it, Socrates, when you do not know at all what it is? How will you aim to search for something you do not know at all? If you should happen to meet with it, how will you know that this is the thing that you did not know?
SOCRATES: I know what you want to say, Meno. Do you realise what a debater’s argument you are bringing up, that a man cannot search either for what he knows or for what he does not know? He cannot search for what he knows – since he knows it, there is no need to search – nor for what he does not know, for he does not know what to look for.

8. Meno’s Paradox The Paradox of Inquiry
The ‘accounts’ are attempts to solve this
They all fail
Thus it is impossible to learn new things
Thus
All knowledge is impossible OR
We already know everything that can be known

9. The Theory of the Forms There is a way we can know things
There are non-mental and non-physical ‘Forms’ (ideas in Greek)
Things in the world are what they are because they are in some way connected to their Forms
We can know things only through ‘acquaintance’ with their Forms
We make this acquaintance before our birth!

10. The Theory of the Forms Forms explain the possibility of general terms
We can call many things by one name
All things which are dogs we can call a dog.
There must be something which is:
Common to all things called by a general term
Distinctive of all those things
This thing is
Not physical – not all dogs have any physical trait
Recognisable by us – but not by our senses

11. The Theory of the Forms Forms explain the possibility of judgement
All judgement is a type of comparing
‘This is a dog’ means I am comparing ‘this’ to some standard of dogginess
The standard can’t be another dog – else I have to first judge that that is a dog, and so on
The standard can’t be my idea of a dog – it is the idea of a dog only because it is judged to represent dogs accurately. So I still need to judge its dogginess; and so on.

12. The Theory of the Forms Forms explain the possibility of judgement
The standard of ‘dog’ can’t be physical or mental
It is metaphysical
It is that in virtue of which
All things properly called ‘dog’ are properly so called
Only things properly called ‘dog’ are properly so called
We call it the Form of dog, or dog-in-itself, …

13. The Theory of the Forms How do Forms relate to their particulars?
Transcendence: there is far more to the Forms than the particular things which fall under them
Immanence: the Forms are present in their particulars, but not in a way that we can perceive through our senses

14. The Theory of the Forms How do we come to know of them?
Not by our external senses (perception)
Not by our internal sense (awareness)
But by intellectual perception or awareness of the understanding
(Whatever those might be)

15. The Theory of the Forms Who is capable of knowing them?
We are all able to use the term ‘dog’ correctly,
So we are all ‘intellectually aware’ of the Form of Dog
Dog is the Form of a mundane thing – it is a ‘lower’ Form
‘Higher’ Forms are of things such as Triangle, Courage, Equal, Noble, …
Only those trained as intellectuals can ‘perceive these in their understanding’

16. How we Know How do we come to know the higher Forms?
Plato gives an example in the Meno
A slave is taught to double a square
Slave thinks he knows but gives the wrong answer at first before Socrates begins to question him
This also shows the value of elenchus
Socrates then gets the slave to give the right answer
Since the slave only answered questions, he must have known how to double a square already

17. The Allegory of the Cave
What is the difference between how normal people see the world and how philosophers see it?

18. The Objects of Knowledge
Only the Forms are objects of real knowledge
They are permanent, unchanging, always true
What is learnt through the senses is ‘opinion’
It is impermanent, changeable, sometimes true and sometimes not
Plato is contradicted by Aristotle, as we shall see